[apple/xnu.git] / bsd / man / man2 / rename.2

.\"	$NetBSD: rename.2,v 1.7 1995/02/27 12:36:15 cgd Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)rename.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt RENAME 2
.Os BSD 4.2
.Sh NAME
.Nm rename
.Nd change the name of a file
.Sh SYNOPSIS
.Fd #include <stdio.h>
.Ft int
.Fo rename
.Fa "const char *old"
.Fa "const char *new"
.Fc
.Sh DESCRIPTION
The
.Fn rename
system call causes the link named
.Fa old
to be renamed as
.Fa new .
If 
.Fa new
exists, it is first removed.
Both 
.Fa old
and
.Fa new
must be of the same type
(that is, both must be either directories or non-directories)
and must reside on the same file system.
.Pp
The
.Fn rename
system call guarantees that an instance of
.Fa new
will always exist,
even if the system should crash in the middle of the operation.
.Pp
If the final component of
.Fa old
is a symbolic link,
the symbolic link is renamed,
not the file or directory to which it points.
.Sh CAVEAT
The system can deadlock if a loop is present in the file system graph.
This loop takes the form of an entry in directory
.Ql Pa a ,
say
.Ql Pa a/foo ,
being a hard link to directory
.Ql Pa b ,
and an entry in
directory
.Ql Pa b ,
say
.Ql Pa b/bar ,
being a hard link
to directory
.Ql Pa a .
When such a loop exists and two separate processes attempt to
perform
.Ql rename a/foo b/bar
and
.Ql rename b/bar a/foo ,
respectively, 
the system may deadlock attempting to lock
both directories for modification.
.Pp
Whether or not hard links to directories are supported is specific to
the underlying filesystem implementation.
.Pp
It is recommended that any hard links to directories in an underlying
filesystem should be replaced by symbolic links by the system administrator
to avoid the possibility of deadlocks.
.Sh RETURN VALUES
A 0 value is returned if the operation succeeds, otherwise
.Fn rename
returns -1 and the global variable 
.Va errno
indicates the reason for the failure.
.Sh ERRORS
The
.Fn rename
system call will fail and neither of the argument files will be
affected if:
.Bl -tag -width Er
.\" ===========
.It Bq Er EACCES
A component of either path prefix denies search permission.
.\" ===========
.It Bq Er EACCES
The requested operation requires writing in a directory
(e.g.,
.Fa new ,
new/.., or old/..) whose modes disallow this.
.\" ===========
.It Bq Er EDQUOT
The directory in which the entry for the new name
is being placed cannot be extended because the
user's quota of disk blocks on the file system
containing the directory has been exhausted.
.\" ===========
.It Bq Er EFAULT
.Em Path
points outside the process's allocated address space.
.\" ===========
.It Bq Er EINVAL
.Fa Old
is a parent directory of
.Fa new ,
or an attempt is made to rename
.Ql \&.
or
.Ql \&.. .
.\" ===========
.It Bq Er EIO
An I/O error occurs while making or updating a directory entry.
.\" ===========
.It Bq Er EISDIR
.Fa new
is a directory, but
.Fa old
is not a directory.
.\" ===========
.It Bq Er ELOOP
Too many symbolic links are encountered in translating either pathname.
This is taken to be indicative of a looping symbolic link.
.\" ===========
.It Bq Er ENAMETOOLONG
A component of a pathname exceeds 
.Dv {NAME_MAX}
characters, or an entire path name exceeds
.Dv {PATH_MAX}
characters.
.\" ===========
.It Bq Er ENOENT
A component of the
.Fa old
path does not exist,
or a path prefix of
.Fa new
does not exist.
.\" ===========
.It Bq Er ENOSPC
The directory in which the entry for the new name is being placed
cannot be extended because there is no space left on the file
system containing the directory.
.\" ===========
.It Bq Er ENOTDIR
A component of either path prefix is not a directory.
.\" ===========
.It Bq Er ENOTDIR
.Fa old
is a directory, but
.Fa new
is not a directory.
.\" ===========
.It Bq Er ENOTEMPTY
.Fa New
is a directory and is not empty.
.\" ===========
.It Bq Er EPERM
The directory containing
.Fa old
is marked sticky,
and neither the containing directory nor
.Fa old
are owned by the effective user ID.
.\" ===========
.It Bq Er EPERM
The
.Fa new
file exists,
the directory containing
.Fa new
is marked sticky,
and neither the containing directory nor
.Fa new
are owned by the effective user ID.
.\" ===========
.It Bq Er EROFS
The requested link requires writing in a directory on a read-only file
system.
.\" ===========
.It Bq Er EXDEV
The link named by
.Fa new
and the file named by
.Fa old
are on different logical devices (file systems).
Note that this error code will not be returned
if the implementation permits cross-device links.
.El
.Sh CONFORMANCE
The restriction on renaming a directory whose permissions disallow writing
is based on the fact that UFS directories contain a ".." entry.
If renaming a directory would move it to another parent directory,
this entry needs to be changed.
.Pp
This restriction has been generalized to disallow renaming
of any write-disabled directory,
even when this would not require a change to the ".." entry.
For consistency, HFS+ directories emulate this behavior.
.Sh SEE ALSO
.Xr open 2 ,
.Xr symlink 7
.Sh STANDARDS
The
.Fn rename
function conforms to 
.St -p1003.1-88 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: rename.2,v 1.7 1995/02/27 12:36:15 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1983, 1991, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)rename.2 8.1 (Berkeley) 6/4/93
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt RENAME 2
	38	.Os BSD 4.2
	39	.Sh NAME
	40	.Nm rename
	41	.Nd change the name of a file
	42	.Sh SYNOPSIS
	43	.Fd #include <stdio.h>
	44	.Ft int
2d21ac55 A	45	.Fo rename
	46	.Fa "const char *old"
	47	.Fa "const char *new"
	48	.Fc
9bccf70c	49	.Sh DESCRIPTION
2d21ac55 A	50	The
	51	.Fn rename
	52	system call causes the link named
	53	.Fa old
9bccf70c	54	to be renamed as
2d21ac55	55	.Fa new .
9bccf70c	56	If
2d21ac55	57	.Fa new
9bccf70c A	58	exists, it is first removed.
9bccf70c A	59	Both
2d21ac55	60	.Fa old
9bccf70c	61	and
2d21ac55 A	62	.Fa new
	63	must be of the same type
	64	(that is, both must be either directories or non-directories)
	65	and must reside on the same file system.
9bccf70c	66	.Pp
2d21ac55 A	67	The
	68	.Fn rename
	69	system call guarantees that an instance of
	70	.Fa new
	71	will always exist,
	72	even if the system should crash in the middle of the operation.
9bccf70c A	73	.Pp
9bccf70c A	74	If the final component of
2d21ac55	75	.Fa old
9bccf70c A	76	is a symbolic link,
	77	the symbolic link is renamed,
	78	not the file or directory to which it points.
	79	.Sh CAVEAT
2d21ac55	80	The system can deadlock if a loop is present in the file system graph.
9bccf70c A	81	This loop takes the form of an entry in directory
	82	.Ql Pa a ,
	83	say
	84	.Ql Pa a/foo ,
	85	being a hard link to directory
	86	.Ql Pa b ,
	87	and an entry in
	88	directory
	89	.Ql Pa b ,
	90	say
	91	.Ql Pa b/bar ,
	92	being a hard link
	93	to directory
	94	.Ql Pa a .
	95	When such a loop exists and two separate processes attempt to
	96	perform
	97	.Ql rename a/foo b/bar
	98	and
	99	.Ql rename b/bar a/foo ,
	100	respectively,
	101	the system may deadlock attempting to lock
	102	both directories for modification.
2d21ac55 A	103	.Pp
	104	Whether or not hard links to directories are supported is specific to
	105	the underlying filesystem implementation.
	106	.Pp
	107	It is recommended that any hard links to directories in an underlying
	108	filesystem should be replaced by symbolic links by the system administrator
	109	to avoid the possibility of deadlocks.
9bccf70c A	110	.Sh RETURN VALUES
	111	A 0 value is returned if the operation succeeds, otherwise
	112	.Fn rename
	113	returns -1 and the global variable
	114	.Va errno
	115	indicates the reason for the failure.
	116	.Sh ERRORS
2d21ac55 A	117	The
	118	.Fn rename
	119	system call will fail and neither of the argument files will be
9bccf70c A	120	affected if:
9bccf70c A	121	.Bl -tag -width Er
2d21ac55 A	122	.\" ===========
	123	.It Bq Er EACCES
	124	A component of either path prefix denies search permission.
	125	.\" ===========
	126	.It Bq Er EACCES
	127	The requested operation requires writing in a directory
	128	(e.g.,
	129	.Fa new ,
	130	new/.., or old/..) whose modes disallow this.
	131	.\" ===========
	132	.It Bq Er EDQUOT
	133	The directory in which the entry for the new name
	134	is being placed cannot be extended because the
	135	user's quota of disk blocks on the file system
	136	containing the directory has been exhausted.
	137	.\" ===========
	138	.It Bq Er EFAULT
	139	.Em Path
	140	points outside the process's allocated address space.
	141	.\" ===========
	142	.It Bq Er EINVAL
	143	.Fa Old
	144	is a parent directory of
	145	.Fa new ,
	146	or an attempt is made to rename
	147	.Ql \&.
	148	or
	149	.Ql \&.. .
	150	.\" ===========
	151	.It Bq Er EIO
	152	An I/O error occurs while making or updating a directory entry.
	153	.\" ===========
	154	.It Bq Er EISDIR
	155	.Fa new
	156	is a directory, but
	157	.Fa old
	158	is not a directory.
	159	.\" ===========
	160	.It Bq Er ELOOP
	161	Too many symbolic links are encountered in translating either pathname.
	162	This is taken to be indicative of a looping symbolic link.
	163	.\" ===========
9bccf70c	164	.It Bq Er ENAMETOOLONG
2d21ac55	165	A component of a pathname exceeds
9bccf70c	166	.Dv {NAME_MAX}
2d21ac55	167	characters, or an entire path name exceeds
9bccf70c A	168	.Dv {PATH_MAX}
9bccf70c A	169	characters.
2d21ac55	170	.\" ===========
9bccf70c A	171	.It Bq Er ENOENT
9bccf70c A	172	A component of the
2d21ac55	173	.Fa old
9bccf70c A	174	path does not exist,
9bccf70c A	175	or a path prefix of
2d21ac55	176	.Fa new
9bccf70c	177	does not exist.
2d21ac55 A	178	.\" ===========
	179	.It Bq Er ENOSPC
	180	The directory in which the entry for the new name is being placed
	181	cannot be extended because there is no space left on the file
	182	system containing the directory.
	183	.\" ===========
	184	.It Bq Er ENOTDIR
	185	A component of either path prefix is not a directory.
	186	.\" ===========
	187	.It Bq Er ENOTDIR
	188	.Fa old
	189	is a directory, but
	190	.Fa new
	191	is not a directory.
	192	.\" ===========
	193	.It Bq Er ENOTEMPTY
	194	.Fa New
	195	is a directory and is not empty.
	196	.\" ===========
9bccf70c A	197	.It Bq Er EPERM
9bccf70c A	198	The directory containing
2d21ac55	199	.Fa old
9bccf70c A	200	is marked sticky,
9bccf70c A	201	and neither the containing directory nor
2d21ac55	202	.Fa old
9bccf70c	203	are owned by the effective user ID.
2d21ac55	204	.\" ===========
9bccf70c A	205	.It Bq Er EPERM
9bccf70c A	206	The
2d21ac55	207	.Fa new
9bccf70c A	208	file exists,
9bccf70c A	209	the directory containing
2d21ac55	210	.Fa new
9bccf70c A	211	is marked sticky,
9bccf70c A	212	and neither the containing directory nor
2d21ac55	213	.Fa new
9bccf70c	214	are owned by the effective user ID.
2d21ac55	215	.\" ===========
9bccf70c A	216	.It Bq Er EROFS
	217	The requested link requires writing in a directory on a read-only file
	218	system.
2d21ac55 A	219	.\" ===========
	220	.It Bq Er EXDEV
	221	The link named by
	222	.Fa new
	223	and the file named by
	224	.Fa old
	225	are on different logical devices (file systems).
	226	Note that this error code will not be returned
	227	if the implementation permits cross-device links.
9bccf70c	228	.El
2d21ac55 A	229	.Sh CONFORMANCE
	230	The restriction on renaming a directory whose permissions disallow writing
	231	is based on the fact that UFS directories contain a ".." entry.
	232	If renaming a directory would move it to another parent directory,
	233	this entry needs to be changed.
	234	.Pp
	235	This restriction has been generalized to disallow renaming
	236	of any write-disabled directory,
	237	even when this would not require a change to the ".." entry.
	238	For consistency, HFS+ directories emulate this behavior.
9bccf70c	239	.Sh SEE ALSO
2d21ac55	240	.Xr open 2 ,
9bccf70c A	241	.Xr symlink 7
	242	.Sh STANDARDS
	243	The
	244	.Fn rename
	245	function conforms to
	246	.St -p1003.1-88 .